Sound-recording machine



June 17, 1930. 2 A. W. GEYER 1,764,786

SOUND RECORDING MACHINE Filed June 22, 1928 6 l J 5 Hllll llll lllll HHH i 1 1}}{1 I: H 1 I Illl Hlll Illll lllllll Receiver Patented June 17, 1930 UNITED STATES ALBERT W. GEYER, OI CHICAGO, ILLINOIS I SOUND-RECORDING- MACHINE Application filed June 22,

This ainvention relates to the art of recording sounds generally. .In its preferred embodiment the invention comprises means to receive the air vibrations of sounds, means to transform said air vibrations'into electrical waves free of distortion, means to analyze said electrical waves in their characteristic component frequencies and means to record the sound waves by the action of individual groups of said characteristic component frequencies.

The machine may to great advantage be used for typing speech sounds by'simply allowing the speech sounds to fall upon the diaphragm of the receiver of the machine. Other uses of the machine will be apparent as the specification proceeds.

One form of the invention is illustrated 1n the accompanying drawing, in which Figure 1 is a sectional View of the receiver, Fig. 2 is a plan view of the receiver, Fig. 3, is a current diagram of the network of amplifiers and Wave filters of the machine, Fig. 4, is a view of the recording mechanism.

In the drawing 1 is a diaphragm, made of 'an electrical conductor and said diaphragm is shaped so as to be as aperiodlcal as possible. Diaphragm 1 is suspended in the magnetical field of an electromagnet 2. Both terminals of the diaphragm 1 are closed to an electrical circuit. Sound waves falling upon the diaphragm will cause the latter to vibrate. In vibrating in the magnetic field, the diaphragm 1 sets up an alternating current in the receiver line 3, this current being analogous to the sound wave in frequency, phase and energy.

Said receiver current is transmitted to a network of amplifiers and wave filters or tuned circuits as illustrated in diagram Fig. 3. This network will amplify the sound current and analyze same in its characteristic component frequencies. Current will be passed only by the lines, which are tuned to the main sound current are grouped to enerthe characteristic frequencies of the particu- '1928. Serial 'No. 287,547.

gize individual relays,'one of which is shown in Fig. 4.

Said individual relays have several coils 4, but one armature 5 only. The armature 5 is balanced by the spring 6, to answerthe combined force of all coils only. The armature 5 actuates a recording mechanism, as soon as all coils of the relays are energized. The recording mechanism maybe the lever system of a typewriter.

The operation of the entire mechanism will be clearly understood on reference to the following description. Assuming that speech is to be typed by this, machine, the speech sounds are allowed to fall upon the diaphragm 1 of the receiver. The diaphragm will reproduce the sound vibrations without noticeable distortion. In vibrating in the magnetic field of the electromagnet 2, the diaphragm will set up the main speech current in the receiver line 3, this current Willbe analogous to the speech sound vibrations in frequency, phase and energy, yet the current will be very weak. As this current is impressed upon the input of the amplifier and filter network, it will be amplified and then analyzed in its component frequencies, each individual sound in such a number of characteristic components, as to differentiate it from any other one. The elements of speech may be the sound of a single letter, or the sound of several letters combined, as the sound of an entire syllable. Thus the network of the machine may provide sufiicient filters or tuned circuits, to filter out from the main speech current the characteristic component frequencies of every letter sound or of every syllable sound, in sequence as they fall upon the diaphragm. The network may also be made variable, to allow tuning to individual voices. The groups of filtered circuits, representing the characteristics of the letters or syllables, will energize their corresponding individual relays, selectivity being insured due to fact that each relay will act only, when all its coils are energizedfln other words when every characteristic component frequency is present. The relays, energized in sequence as the speech sounds enter the receiver, will actuate the levers of an ordinary typewriter, thus typing letter by letter,

or syllable by syllable, or both combined.

In the same way, the machine may type telephone calls, by allowing the telephone sounds to fallupon the diaphragm of the machine.

Having thus described the invention, what is claimed is:

1. In combination, means to receive sound Waves, means to transform said sound Waves into electrical waves, means to amplify and analyze said electrical Waves in their characteristic component frequencies, means to group said characteristic, component frequencies in individual groups, and means to record the sound waves by the action of said individual groups of characteristic component frequencies.

2. In combination, aperiodical means to receive sound waves, means to transform said sound waves into electrical Waves, means to amplify and analyze said electrical waves in their characteristic component frequencies, means to group said characteristic component frequencies in individual groups, and means to record the sound'waves by: the action of said individual groups of characteristic component frequencies.

3. In combination, means to receive sound waves, means to transform sound Waves into electrical waves, means to amplify'said electrical waves, means, adapted to analyze individual electrical Waves, originating from individual sound waves, in their characteristic component frequencies, means to group said characteristic component frequencies in individual groups, and means to record the sound waves by the action of said individual groups of characteristic component frequencies.

4. A sound recording machine as specified in claim 1 wherein the last named means are adapted to record steady state sound waves,

of said electromagnet, such electrical conwaves, means to transform said sound Waves ductor reproducing sound vibrations without distortion and setting up a true sound current, means to amplify and analyze said sound current in its characteristic component frequencies, means to group said characteristic component frequencies in individual groups, and means to record the sound waves by the action of said individual groups of characteristic component frequencies.

6. In combination, means to receive sound into electrical waves, amplifiers to amplify said electrlcal Waves, a variable electrical network, to analyze said electrical waves in their characteristic component frequencies, means to group said characteristic component frequencies in individual groups, and means to said relays.

ALBERT W. GEYER. 

